Associations of obesity with antidiabetic medication use after living kidney donation: An analysis of linked national registry and pharmacy fill records

We examined a novel linkage of national US donor registry data with records from a pharmacy claims warehouse (2007‐2016) to examine associations (adjusted hazard ratio, LCLaHRUCL) of post‐donation fills of antidiabetic medications (ADM, insulin or non‐insulin agents) with body mass index (BMI) at donation and other demographic and clinical factors. In 28 515 living kidney donors (LKDs), incidence of ADM use at 9 years rose in a graded manner with higher baseline BMI: underweight, 0.9%; normal weight, 2.1%; overweight, 3.5%; obese, 8.5%. Obesity was associated with higher risk of ADM use compared with normal BMI (aHR, 3.364.596.27). Metformin was the most commonly used ADM and was filled more often by obese than by normal weight donors (9‐year incidence, 6.87% vs 1.85%, aHR, 3.555.007.04). Insulin use was uncommon and did not differ significantly by BMI. Among a subgroup with BMI data at the 1‐year post‐donation anniversary (n = 19 528), compared with stable BMI, BMI increase >0.5 kg/m2 by year 1 was associated with increased risk of subsequent ADM use (aHR, 1.031.482.14, P = .04). While this study did not assess the impact of donation on the development of obesity, these data support that among LKD, obesity is a strong correlate of ADM use.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/152001/1/ctr13696_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/152001/2/ctr13696.pd

UNDERSTANDING POST-DONATION KIDNEY FUNCTION IN LIVING KIDNEY DONORS

Living donors provide a third of the kidney transplants each year in the United States. Because donor nephrectomy is truly elective, transplant providers must offer personalized risk estimates to people considering kidney donation, as well as individualized post-donation care. This dissertation focuses on post-donation kidney function and the association of early post-donation outcomes with recipient graft outcomes. First, since hypertension and diabetes are the predominant causes of end-stage renal disease (ESRD) in living kidney donors, we sought to clarify their early post-donation incidence rates (Chapter 2). Using national registry data, we estimated 310 per 10,000 donors developed hypertension within 2-years of donation, while only 15 per 10,000 donors developed diabetes. We then focused on hypertension and obesity and their association with post-donation renal function (Chapters 3 and 4). We compared a cohort of 1295 donors to a weighted cohort of 8233 healthy non-donors. We found that kidney donation was independently associated with a 19% higher risk of hypertension and that donors who developed hypertension had a plateau in the usual post-donation increase of estimated glomerular filtration rate (eGFR). We also found that donor eGFR trajectory varied by obesity. Non-obese donors had an increase in eGFR of +0.55 mL/min/year while obese donors had an attenuated increase of +0.30 mL/min/year. In comparison, obese and non-obese non-donors had a similar decrease in eGFR over time. Finally, we studied early post-donation markers of donor renal function and recipient graft outcomes using national registry data (Chapters 5 and 6). Given that donor ESRD is associated with recipient graft loss, we found that the risk of recipient graft loss increased with each decrement in 6-month post-donation eGFR. Last, although hypertension is a frequent causes of donor ESRD, we found iii that recipients whose donors developed incident hypertension within 2-years post-donation had no higher risk of graft loss. Our results will be used by nephrologists and transplant surgeons to better personalize counseling for people considering living kidney donation as well as better individualize post-donation care

Transplant waitlisting attenuates the association between hemodialysis access type and mortality

Prior studies have shown that beginning hemodialysis (HD) with a hemodialysis catheter (HC) is associated with worse mortality than with an arteriovenous fistula (AVF) or arteriovenous graft (AVG). We hypothesized that transplant waitlisting would modify the effect of HD access on mortality, given waitlist candidates' more robust health status. Using the US Renal Data System, we studied patients with incident ESRD who initiated HD between 2010 and 2015 with an AVF, AVG, or HC. We used Cox regression including an interaction term for HD access and waitlist status. There were 587,607 patients that initiated HD, of whom 82,379 (14.0%) were waitlisted for transplantation. Only 26,264 (4.5%) were transplanted. Among patients not listed, those with an AVF had a 34% lower mortality compared to HC [adjusted hazard ratio (aHR) 0.66, 95% confidence interval (CI) 0.65-0.67] while those with an AVG had a 21% lower mortality compared to HC (aHR 0.79, 95% CI 0.77-0.81). Transplant waitlisting attenuated the association between hemodialysis access type and mortality (interaction p < 0.001 for both AVF and AVG vs. HC). Among patients on the waitlist, those with an AVF had a 12% lower mortality compared to HC (aHR 0.88, 95% CI 0.84-0.93), while those with an AVG had no difference in mortality (aHR 0.95, 95% CI 0.84-1.08). While all patients benefit from AVF or AVG over HC, the benefit was attenuated in waitlisted patients. Efforts to improve health status and access to healthcare for non-waitlisted ESRD patients might decrease HD-associated mortality and improve rates of AVF and AVG placement

Association Between Living Kidney Donor Postdonation Hypertension and Recipient Graft Failure.

BACKGROUND: Recipients of kidneys from living donors who subsequently develop end-stage renal disease (ESRD) also have higher graft failure, suggesting the 2 donor kidneys share risk factors that could inform recipient outcomes. Given that donor ESRD is rare, an earlier and more common postdonation outcome could serve as a surrogate to individualize counseling and management for recipients. Hypertension is a frequent event before donor ESRD; thus, early postdonation hypertension might indicate higher risk of graft failure. METHODS: We studied Scientific Registry of Transplant Recipients data to quantify the association between early postdonation hypertension and recipient graft failure using propensity score-weighted Cox proportional hazards regression. We also examined the association between postdonation systolic blood pressure and graft failure. RESULTS: Of 37 901 recipients, 2.4% had a donor who developed hypertension within 2 years postdonation. Controlling for donor and recipient characteristics, recipients whose donors developed hypertension had no higher risk for graft failure (adjusted hazard ratio [aHR] 1.03, 95% confidence interval [CI] 0.85-1.25, P = 0.72). This was consistent among subgroups of recipients at higher risk for adverse outcomes due to hyperfiltration: African American recipients (aHR 1.10, 95% CI 0.70-1.73, P = 0.68) and those with ESRD caused by hypertension (aHR 1.10, 95% CI 0.65-1.85, P = 0.73) or diabetes (aHR 0.80, 95% CI 0.56-1.13, P = 0.20). However, graft failure was associated with postdonation systolic blood pressure (per 10 mm Hg, aHR 1.05, 95% CI 1.03-1.08, P < 0.001). CONCLUSIONS: Although postdonation systolic blood pressure is associated with graft failure, the reported diagnosis of hypertension as determined by the requirement for blood pressure treatment early postdonation did not portend a higher risk of recipient graft failure in the same way as eventual postdonation ESRD